brazen

With brazen disregard for the sign that said "no cellphones please" the woman took a long call in the doctor's office waiting room. Brazen refers to something shocking, done shamelessly.

The Middle English word was brasen "made of brass," from Old English bræsen, from bræs "brass." In fact a near synonym of brazen is our English word brassy, which has the additional meaning of being loud and showy.